HierarchyLayoutAlgorithm (OpenNMS 29.0.10 API)

java.lang.Object
- org.opennms.features.topology.app.internal.jung.AbstractLayoutAlgorithm
- - org.opennms.features.topology.app.internal.jung.HierarchyLayoutAlgorithm

All Implemented Interfaces:

LayoutAlgorithm, LayoutConstants
```
public class HierarchyLayoutAlgorithm
extends AbstractLayoutAlgorithm
```
Algorithm to transform a graph of vertices and edges into a hierarchical structure of a 2D plane. It is a geometric transformation which does not change the graph but the x and y position of its vertices.

The algorithm generates the layout correctly if only one root element exists or if there are no vertices at all If no root element exists, a random vertex from the graph is picked and defined as root. If multiple root elements exist, a parent of those is created and called dummy root element. This ensures that there is only one root element.

The current graph to be transformed is extracted from the GraphContainer. Basically all its vertices are transformed and then the new layout is set back to the GraphContainer by executing the updateLayout method.
The Algorithm uses the JUNG library.

See Also:

JUNG Framework (Java Universal Network/Graph Framework)

Field Summary
- Fields inherited from interface org.opennms.features.topology.app.internal.jung.LayoutConstants
  ELBOW_ROOM, LAYOUT_HEIGHT, LAYOUT_WIDTH, SPRING_FORCE_MULTIPLIER, SPRING_LAYOUT_REPULSION

Constructor Summary

Constructors
Constructor Description

HierarchyLayoutAlgorithm()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`updateLayout(Graph graph)`	Updates the current layout by extracting the containers graph and then perform a (x,y) tranformation of all vertices.

Methods inherited from class org.opennms.features.topology.app.internal.jung.AbstractLayoutAlgorithm
initializer, initializer, selectLayoutSize

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - HierarchyLayoutAlgorithm
```
public HierarchyLayoutAlgorithm()
```
- Method Detail
  - updateLayout
```
public void updateLayout(Graph graph)
```
    Updates the current layout by extracting the containers graph and then perform a (x,y) tranformation of all vertices.
    
    Specified by:
    
    updateLayout in interface LayoutAlgorithm
    
    Specified by:
    
    updateLayout in class AbstractLayoutAlgorithm
    
    Parameters:
    
    graph - The container of the current graph. Contains all relevant information to perform the transformation of the Graph by changing its Layout